Generally, touch-screen display devices are capable of detecting input from a user by detecting the presence and location of a touch on, within, or within the vicinity of the surface of the display area. Some touch-screen display devices require that a user physically touch the surface of the display area, for example with a finger, stylus, or other input mechanism, in order to engage the surface of the touch-screen display device. Other touch-screen display devices are capable of receiving input by detecting that a user's finger, a stylus, or some other input mechanism has engaged the surface of the touch-screen display device by hovering around, or otherwise in the vicinity of, a particular location on the surface of the display area.
Multi-touch display devices are more sophisticated than traditional touch-screen display devices and are capable of detecting the presence and location of multiple touches on, within, or within the vicinity of the surface of the display area at the same time. Like traditional touch-screen display devices, some multi-touch display devices require that a user physically touch the surface of the display area with one or more fingers, styluses, and/or other mechanisms in order to engage the surface of the multi-touch display device, while other multi-touch display devices are capable of receiving input by detecting that one or more fingers, styluses, and/or other input mechanisms have engaged the surface of the multi-touch display device by hovering around, or otherwise in the vicinity of, the surface of the display area.
Multi-touch display devices belong to a more general class of multi-point input computing systems. Multi-point input computing systems receive, recognize, and act upon multiple inputs at the same time.